Snap switch



SNAP SWITCH Donald H. Mink, 479 Park St, Elgin, Ill.

Filed Feb. 25, 1953, Set. N0. 717,498

6 Claims. (Cl. Ziiil-67) This invention is concerned with the art of electric switches, particularly snap switches.

As is well known, when switch contacts are moved in or out of engagement there is a tendency for arcing to occur across the contacts. This burns the contacts, and eventualy renders them inoperative. Accordingly, various expedients have been developed for causing switches to open and close with a snap action. In general, such switches have used spring devices which in some respects have been entirely satisfactory. However, such switches have been subject to spring fatigue, and sometimes have been damaged or thrown out of adjustment by vibration or temperature changes. Furthermore, such switches have generally been somewhat complicated mechanically, and often have involved difficult fabrication problems.

Accordingly, it is an object of this invention to provide an improved and simplified snap switch.

Furthermore, it is an object of this invention to provide a snap switch which has no components under compression or tension at any time, thereby substantially eliminating fatigue in components.

It is another object of this invention to provide a snap switch which is substantially uneffected by vibration or temperature changes.

Still another object of this invention is to provide an electric switch wherein a common agency is used for pivotally mounting the switch and for imparting a snap action thereto.

A more specific object of this invention is to provide an electric switch incorporating a permanent magnet attracting certain of the components of the switch into predetermined position.

Other and further objects and advantages of the present invention will be apparent from the following description when taken in connection with the accompanying drawings wherein Fig. 1 is a perspective view of a switch incorporating the principles of this invention;

Fig. 2 is a longitudinal sectional view through the switch as taken substantially along the line 2- 2 in Fig. 1 on a vertical plane;

Fig. 3 is a horizontal sectional view taken substantially along the line 3-3 in Fig. 2;

Fig. 4 is a perspective view of a modified form of switch;

Fig. 5 is a longitudinal sectional view on a vertical plane substantially along the line 5-5 in Fig. 4;

Fig. 6 is a horizontal longitudinal sectional view taken substantially along the line 6-6 in Fig. 5;

Fig. 7 is a perspective view of a further modification; and

Fig. 8 is a perspective view of yet another modification of the invention.

Referring now in greater particularity to the drawings, and first to Figs. 1-3, there will be seen a switch constructed in accordance with the principles of this invenmamas Patented Aug. 30, 1960 tion and designated generally by the numeral 10. The switch includes a housing 12 enclosed on three sides and both ends, and open on the bottom. It will be appreciated that a removable or a sealed bottom closure member could be provided as necessitated by various installation requirements, but this has not been shown since it is well known in the art. A metal bushing 14 is fixed in the top of the case or housing 12 and a cylinder actuator or button 16 having a pointed inner end 18 extends through the bushing. The actuator has a flange 20 within the case or housing limiting outward movement of the actuator. A mounting block 22 of insulating material is secured within the case or housing by means such as screws 24. A pair of generally U- shaped terminals 26 and 2,8 is mounted in a pair of spaced recesses extending around the end of the block 22 in the vicinity of the actuator 16. The. terminal strips 26 and 28 are respectively provided with contacts 30 and 32 on the upper ends thereof, and the lower ends thereof are provided with threaded embossments, one of which is indicated at 34, for receiving terminal screws 36. The embossments and the screws extend into suitable apertures 33 in the base or block 22.

A permanent magnet 41 is mounted at the opposite end of the base or block 22 from the terminal strips 22, preferably being bonded to the block or base. The magnet 40 is of the same width as the base or block 22, and extends above the base as indicated at 42. The magnet is substantially smaller in the direction of the length of the base 22 (i.e. horizontal, as viewed in Fig. 2) than it is in height. The magnet is polarized at the top and bottom thereof.

A generally L-shaped armature 44- of soft iron rests on top of the magnet. The angle of the armature 44 is very slightly obtuse, being just greater than The short arm 46 of the armature is normally held by magnetic attraction against the side of the magnet 4a. The longer arm 48 extends forwardly above the base or block 22 and terminates beneath the actuator 16. An insulating member 59 carries a bridging contact 52 designed to engage the contacts 3% and 32 simultaneously. As will be apparent, the length of the arm an adjacent the side of the magnet 44 is much greater than the portion of the arm 48 adjacent the top of the magnet. Hence, the armature is normally held in the solid line position shown, with the arm 46 fiat against the side of the magnet, and the bridging contact 52 lifted from the contacts 39. The magnetic attraction of the magnet on the armature, both on the arm 46 and on the arm 43, renders any additional securing means unnecessary, the armature simply pivoting at its apex on the corresponding corner of the magnet.

When the actuator '16 is pressed, the magnetic force is overcome and the bridging contact 52 is brought into engagement with the contacts 30 and 32. When the actuator 16 is released, the magnet pulls the arm 46 in against the side of the magnet, thereby returning the actuator to its initial position, and opening the switch contact with a snap action, thereby avoiding burning of the switch contacts.

A modification of the invention is shown in Figs. 4-6. Many of the parts are functionally or structurally similar to those heretofore shown and described, and similar numerals are utilized with the addition of the sufiix a. The switch 10:: comprises a two-piece housing or case 12:: joined along the horizontal median plane by cement or the like. A pair of terminals 26a is mounted directly on the floor of the housing, being recessed therein and extending through an aperture 54- at the end of the housing. In this instance, the terminals are not shown as having separate contact members thereon, but it will be appreciated that such contacts could be provided.

The floor of the housing, hereinafter identified by the numeral 56, slopes downwardly from thecenter toward both ends, as best will be seen in Fig. 5. A magnet 4l3a is mounted at the peak of the floor. The magnet-is of more or less flat, practically sheet metal construction, and is bent slightly along its center line to conform to the top surface of the floor 56 in which it is embedded. The magnet further is transversely crimped' to provide a ridge 58. The specific configuration of this ridge, whether providing a knife-edge top surface, or a cylindrical top surface, or the like depends on the requirements of the switch.

An armature 44a is provided with a similar crimp providing a concave bearing 60 received on the ridge 58. The arms 46a and 48a of the armature 44a are colinear,

extending in opposite directions from the bearing 60,

and being of equal length. The armature 44a is recessed in the under surface of an actuator 16a in the form of an insulating beam having an upward projection 62 adjacent one end, and an upward projection 64 adjacent the opposite end. These projections respectively extend through apertures 66 and 68 in the top of the housing or case. A depending ridge or dimple 70 prevents the actuator 16 from being moved by shock or the like upward a suflicient distance to allow the bearing 60 to move off the ridge 58.

Adjacent the right end of the actuator 16 and directly above the terminal strips 26:: there is a bridging contact 52a recessed in the actuator. The switch is shown in the off position, in which the armature arm 46a is held down against the adjacent end or pole of the permanent magnet 40a. The projection 64 comprises an on" button, and upon depression thereof the arm 46a is moved away from the magnet, and the arm 48a is brought closer to the magnet. As soon as the arm 48a has come closer to the magnet than is the arm 4611, the arm 48a is snapped into engagement with the magnet, thereby bringing the bridging contact 52a down across the terminal strips 26a, 28a. The switch will stay in this position until the projection 62, which comprises an off button is depressed, at which time the action is reversed. As will be apparent, this switch gives a snap action in either direction. It will be obvious that the switch a could be a doublepole double-throw switch with the addition of only a pair of terminal strips and another contact, or the contact shown could be made to bridge the additional pair of terminal strips. Since this is well known in the art, a specific illustration thereof is entirely unnecessary. v

A somewhat different embodiment of the invention is shown in Fig. 7. Although some of the parts differ notably in physical construction, many of the parts are functionally similar to those heretofore shown and described, and are identified by similar numerals with the addition of the suflix b. The switch 1% in Fig. 7 is shown without a case or housing, although it will be appreciated that this is a question of little moment. The

switch includes a base 22b having a pair of upstanding arms 72 thereon. The magnet 40b is mounted in a web between the arms, and has both ends exposed. The armature 44b is U-shaped, and is pivoted on a pin 74 through the upper portion of the arms 72. The arms depend on opposite sides of the magnet 40b, and are alternatively engageable with the ends of the magnet. A substantially U-shaped insulating sheet 76 overlies the armature, and is aflixed thereto. At the lower left corner of the insulating sheet 76, as viewed in Fig. 7, there is a bridging contact 5212.

A pair of substantially L-shaped terminal or contact strips 26b and 28b is embedded in the base 22b and has angularly disposed ends or contacts 3% and 321; respectively positioned for engagement by the bridging contact 52b.

As shown in Fig. 7, the switch is; in on position.'

The right side of the armature is held against the unseen face of the magnet 40b, and the bridging contact 52b con nects the contacts 3% and 32b. When the actuator 16b at the apex of the insulating covering 76b is moved to the left, the right arm of the armature is moved away from the unseen face of the magnet, and the left arm is brought adjacent the left face of .the magnet. After the armature has moved a sufficient distance for the attractive force on the left arm of the armature to be greater than that on the right arm, the switch is snapped to open position. Closing of the switch is converse to the action just described, and will be apparent.

A further modification of the invention is shown in Fig. 8. This modification is structurally somewhat closer to Fig. 7 than the previous embodiments, but functions of the various parts are similar to those previously described. Similar numerals are again used with the addition of the suflix c.

More particularly, the switch includes a base 2% having a pair of upstanding arms 72c thereon. The armature in this instance is fixed to the arms 72c, being generally u-snaped as indicated at 440 (with an open bight), and having a pair of arms 46c and 430. The actuator 16c comprises an insulating paddle pivoted at 74c within the armature 44c, and provided with an inserted permanent magnet 40c. A metal sheet 78 is inserted in the end of the actuator 16c, extending therefrom and having an angularly disposed tip 80 carrying a pair of engagement or contact members 520. The contact members 52c act with the metal sheet 78, 80 to bridge a pair of inserted terminal strips 260 and 280 extending from the left end of the base 22c and exposed at the upper surface thereof. Although no case or housing is shown in this instance, it will be appreciated that such could be provided, if so desired.

The switch iiic is in on position in Fig. 8, and it will be observed that the back surface or face of the magnet 4th: is engageable With the armature arm 48c, thus holding the contact 520 against the. contacts 26c and 280. When the actuator is moved manually, the magnet moves away from the armature arm 48c and toward the arm 460. When it is positioned closer to the arm 260' it is snapped against this arm by magnetic attraction, thus rapidly completing breaking of the contacts, and minimizing arcing. As will be appreciated, movement of the switch back to the on position is similar, the contacts closing with a snap action.

The various embodiments of the invention as herein shown and described will be understood as being exemplary. Various changes in structure will no doubt occur to those skilled in the art, and are to be understood as forming a part of this invention insofar as they fall within the spirit and scope of the appended claims.

The invention is claimed as follows:

1. A snap switch comprising a base, fixed contact means carried by said base, a first magnetic member, a second magnetic member, one of said magnetic members being a permanent magnet and the other of said magnetic members being a magnetically susceptible armature, means fixedly mounting one of said magnetic members on said base, a part of one of said magnetic members providing a fulcrum, the other of said magnetic members being pivotally mounted on said fulcrum and having parts alternatively movable toward and away from the magnetic member fixed on the base, magnetic attraction holding said members together, the permanent magnet of one of said magnetic members effecting a magnetic snap action upon such movement, and contact means carried between one of said magnetic members .pivotally mounted on said fulcrum and selectively enfulcrum providing means comprises a ridge on a face of the permanent magnet.

4. A snap switch comprising a base, fixed contact means carried by said base, a permanent magnet fixed to said base and having two substantially right angularly disposed sides exposed and having an apex between them, a substantially L-shaped armature having an obtuse angle and pivotally mounted on said apex, said armature being held on said apex on said magnet solely by magnetic attraction, said substantially L-shaped armature having a pair of arms respectively adjacent different surfaces of said magnet, one of said arms having a substantially greater length exposed to said magnet than has the other of said arms, the arm having the greater exposed length thereby being magnetically held in contact with the adjacent face of the permanent magnet, movable contact means carried by the armature and selectively engageable with the fixed contact means, and manually operable actuator means engageable with said armature for overcoming the magnetic attraction on the arm having the greater length exposed to the magnet, whereby to pivot said armature about said apex of said magnet to vary the condition of contact engagement.

5. A snap switch comprising a base having a central ridge and a pair of surfaces sloping downwardly there from at a large obtuse angle, a permanent magnet on said base and having an apex positioned above the apex of the base and having surfaces sloping downwardly therefrom substantially parallel to the surfaces of said base, contact means carried by said base and spaced down one of said sloping surfaces from the apex of the base, a rocking member, an armature fixed to said rocking member and pivoting on the apex of the magnet, contact means carried by the rocking member and selectively engageable with the fixed contact means on the base, and manually operable means for pivoting the rocking member back and forth about the apex of the permanent magnet, magnetic attraction of the permanent magnet on the armature holding the armature on the magnet, and snapping the armature against either of the sloping surfaces of the permanent magnet.

6. A snap switch comprising a base, fixed contact means carried by said base, a block-like permanent magnet carried by said base and having a plurality of exposed faces, an armature having a pair of angularly arranged magnetically susceptible portions each alternatively engageable with a face of said block-like magnet, said armature being pivotable substantially directly on said block-like magnet, movable contact means carried by the armature, and manually operable means engageable with said armature for overcoming the magnetic attraction of said block-like magnet on one armature portion whereby to bring the other armature portion into engagement with said block-like magnet with a snap action to vary the condition of contact engagement.

References Cited in the file of this patent UNITED STATES PATENTS 1,108,320 Berdon Aug. 25, 1914 1,989,277 Jeffrey Ian. 29, 1935 2,436,224 Ogle Feb. 17, 1948 2,550,546 Flight Apr. 24, 1951 2,665,344 Zozulin Jan. 5, 1954 2,707,215 Chinn Apr. 26, 1955 2,742,537 Leslie Apr. 17, 1956 FOREIGN PATENTS 163,579 Australia June 24, 1955 

